13

I have two monitors connected to my PC: One computer monitor via DisplayPort and a TV via HDMI. The TV isn't in the same room as my PC, so it's pretty tough to select which operative system to launch in GRUB when I boot my PC.

Is it possible to change which computer monitor my PC uses to display it's splash screen, BIOS, boot loader etc? If so, how can it be done?

I have an Asus SABERTOOTH Z77 motherboard and a GTX 780 graphics card

Hubro
  • 5,786

3 Answers3

12

Which screen gets BIOS output during the boot process is up to the graphics card. Some graphics cards output to all displays simultaneously, some will only output to whichever port it considers to be "port 1". Most of the time they're not labeled. In the case of multiple graphics cards, the display goes to whichever one the BIOS detects first. Some BIOSes have a setting that lets you determine if an onboard vs. discrete card should be treated as the "primary".

One thing that you should know about TVs specifically is that most of them do not power on their HDMI port unless the TV is actually set to that input. So if your computer is connected to HDMI2, but the TV is set to HDMI1, the computer may not even see that there is a screen attached at all until you switch the TV over to HDMI2.

Also... some BIOSes do not detect whether or not a screen is attached to the primary display and some do. In the cases where it does, "port 1" might change depending on whether the TV is on or set to the right input. In cases where it doesn't, output may go to the HDMI port whether there's anything connected to it or not, and you may not see anything on either screen.

Unfortunately, GRUB loads very early in the boot process before any drivers. It relies on the BIOS to put its menus up on the screen, so you're totally at the mercy of the hardware at that point.

So short answer to your question is "maybe" :-)

Wes Sayeed
  • 13,854
  • Interesting. My HDMI cable is not actually connected directly to the TV, but rather through an amplifier. If I shut the amp down before I boot, I do indeed get BIOS on my PC monitor. That's still not a solution though... :( – Hubro Mar 30 '15 at 23:53
  • 1
    Ahh. Didn't know about the amplifier. That basically tricks the computer into seeing a display on the HDMI port all the time whether the TV is on or not, as long as the amp has power. Obviously your BIOS is treating the HDMI port as "Port 1", so there is little you can do about it unless the BIOS gives you a choice. Only other option would be to get a cheap discrete video card and see if the BIOS will favor that one first. That has its own set of problems though. I think you might be screwed here. – Wes Sayeed Mar 31 '15 at 00:06
  • Almost 6 years later, I now have a Radeon 5700XT, and it only outputs on the HDMI port even if it doesn't have anything plugged into it... The only way to change UEFI settings for me now is to go fetch a HDMI cable and plug the HDMI port to my monitor... Otherwise I'm treated to a black screen until the OS is done loading. – Hubro Feb 03 '21 at 21:45
5

I know the original is question is old, but today I met with the same problem. I have a Gigabyte GTX 1060, and I'm using a TV on HDMI, and a Monitor on Display port. The VGA has 3 Display Ports, 1 HDMI and 1 DVI. Fortunately my problem is solved after I changed the used Display Port (from the farthest to the closest from HDMI). No BIOS change is needed.

Now my monitor shows the boot screen properly. If you didn't try it already, I hope this will help :/.

Zolee
  • 51
  • Exact same situation, though my monitor must use DisplayPort for 144Hz at 1440p, so I can't move that to HDMI to resolve this. – Adambean Dec 27 '19 at 10:55
  • 1
    I know that this answer is old (to an even older question) but I was just struggling myself with the same problem. And I shall say THANK YOU for stating such an obvious thing, as changing the order the cables are attached to graphics card. I have 2 monitors, 1 via DP and 1 via HDMI. The DP one is rotated 90deg (portrait position) so having my BIOS/UEFI or linux login screen was a pain. The card has 4 ports [DP] {HDMI} [DP] [DP]. I've reconnected DP monitor from 1st to 4th port, and now everything works like a charm. Thank you! :) – wojciech_rak Jun 18 '20 at 16:53
  • Thanks from me too! I had the same problem on my RTX 3080, and changing the cables to different ports helped. Somehow I hadn't realized this before, and the card's outputs aren't numbered on the back panel, but I just tried changing to different ports and it helped – Rennex Jul 24 '21 at 13:43
2

<Is it possible to change which computer monitor my PC uses to display it's splash screen, BIOS, boot loader etc? If so, how can it be done?>

I discovered that setting CSM (Compatibility Support Module} in the BIOS to ENABLED caused the desired effect of making my non-TV monitor the posting monitor. I just set it to Enabled but left the other subsettings under it set to "LEGACY" rather than to "UFEI" or "IGNORE". Hope this helps someone.

Operating System - Windows 10 Pro 64-bit * CPU - AMD Ryzen 7 3700X * Motherboard - ASUSTeK COMPUTER INC. ROG STRIX B550-F GAMING (WI-FI) (AM4) * BIOS - UFEI * Display 1: LTV-19w6 * Display 2: SA230

Jerry Schrecker
  • 21
  • I have hdmi and display port monitors connected to same video card. When CSM enabled motherboard uses hdmi monitor, when disabled - display port. Other options under CSM (legacy, uefi) make no difference. – Artem P Mar 30 '21 at 08:16
  • This solution works for my Gigabyte motherboard too. But, CSM mode can't be used together with Secure Boot. And it looks that Windows 11 won't work without Secure Boot. So, it's only a temporary workaround. – Basil Peace Nov 01 '21 at 00:46